Railway-traffic-controlling apparatus



H. W. GRIFFIN ET AL RAILWAY TRAFFIC CONTROLLING APPARATUS April 3, 1928.

Original Filed June 10, 1922 2 Sheets-Shae; 1

mrwzib 33w v a N uvmv INVENTORS L. F. 'Ha ward, '4 H -W, G 'f fin,

' Q- ,1- 25; c he m ATTORNEY April 3, 1928.

H. W. GRIFFIN ET AL RAILWAY TRAFFIC CONTROLLING APPARATUS Original FiledJunelO, 1922 2 sheets sheet 2 Patented Apr. 3, 1928.

UNITED stars HENRY W. GRIFFIN, OF NEW YORK, N. Y., AND LEMUEL F; HOWARD,OF EDGEWOOD ATENT OFFICE.

BOROUGH, PENNSYLVANIA, ASSIGIIOHS Tl) THE UNION SWITCH 85 SIGNAL COM-PANY, OLE E'WISSVALE, PENNSYLVANIA, A CORPORATIQN 0F PENN$YLVANIA.

RAILWAY-TRAFFICcournornrne Arena-Arcs.

Application filed June 10, 1922 Serial No. 567,397. Renewed August 26,1924.

Our invention relates to railway traffic controlling apparatus of thetype wherein traffic governing means located on a car or train iscontrolled by energy received from the trackway, and the supply of atleast a part of such energy from the trackway to the train depends upontratiic conditionsin advance of the train. More specifically, thepresent invention relates to apparatus of this character in which thegoverning means on the train require the constant supply of energy ofthe proper characteristics from the trackway to prevent an automaticapplication of the brakes.

In connection with systems of this na ture, it has been proposed toprovide apparatus which will cause an automatic applica tion of thebrakes when such application Sh uld occur, together with means forpreventing such application by a suitable action on the part of theengineer, and it has also been proposed to causean automatic applicationat a subsequent point if not prevented by a second suitable action onthe part of the engineer.

One feature ofo-ur invention is the provision of a new and improvedmeans for producing an automatic application at such subsequent point toprevent the train proceeding without retardation if such automaticapplication is not properly and safely forestalled by actionofthe'engineer.

We will describe certain forms of apparatus embodying our invention, andwill then point out the novel features thereof in claims.

In the accompanying drawing, Fig, 1 is a' diagrammatic view show ng oneform of apparatus embodying our invention, and Fig. 2 a view showingon,an enlarged scale the vehicle carried receiving coils and receivingcircuits shown in; Fig. 1. Fig. 3 is a View showing a modification ofthe ap-' paratus shown in Fig. 1 and alsoembodying our invention.

Similar reference characters refer to similar parts in each of theseveral views.

Referring first to Fig. l, the reference characters 1 and 1 designatethe track rails of a railway along'which traffic normally moves in thedirection indicated by the arrow. These rails are divided, by insulatedjoints 5.6, into aplurality of track sections designated by thereference character T with an exponent corresponding to the location,which "secondary is connected with the track rails through apole-changer as hereinafter explained. The primary 58 of each of thesetransformers is connected with a transmission line 59 which isconstantly suppliedwith alternating current by a generator 60. The relayfor each section is designatedby the reference character K with anexponent corresponding to the location, and comprises, a winding 61connected across the track rails of the section, and aco-operatingwinding 62 constantly supplied with alternating current bythe secondary 65 of an adjacent transformer" X the primary 58 of whichisconnected with the transmission line 59 Each relay includes a contact 63WhiCl1 0ccupies an intermediate position when the relay is deenergizedand is swung to the right or to the left according as track winding 61is supplied with current of one instantaneous relative polarity or theother.

Located adjacent the entrance end of each track section is aroadsidesignal designated by the reference character L with an eXponent.corresponding to the location. Each of these signals is controlled the:associated track relay K in a usual and-well known manner, but inasmuchasfthe control 1 of the signal has nothing to do with ouixpresentinvention, we have omitted the controlling circuits from the drawings inorder to sim-;

plify the disclosure as much asposs ible.

Suffice itto say, thatwhen a trackrelay is de-energized, the associatedsignal indicates stop; when the track relayis ener gized by trackcurrentof reverse relative po-..

larity (that is. when contact 63 is swung to the left), thesignalindicates caution ,1 and when the relay is energized by trackcurrent of normal relative polarity (that is, when the contact 63 isswung tothe right), the

signal indicates proceed;

IHlJGIPOSBCl-ll'l each tI'ftQlCOlIClllt between" the. transformersecondary 57 and the traclt, rails is a pole-changer whichiie designatedby the reference character Zwith an ex,

ponent corresponding to the location. Each of these pole-changers isoperated by. the adjacent signal L in such manner that current of normalrelative polarity is supplied to the track rails when the signalindicates proceedjor caution, and current of reve 'se relative-polarityis supplied to the track rails y when the signal indicates stop. V

The apparatus thus far referred to is con structed and arranged inaccordance with.

well known principles otrailway signaling,

andrthe operation of this portion of the apparatus will be understoodwithout further explanation,

Each track 'sec'tlon is further provided with'means for supplying linecurrent to the-track rails For this purpose a resistance 68 is connectedacross the track rails atthe entrance endof the section, a secondresistance 68 1s connected across the rails at the-exit end ofthesection, and as shown lll Flg. 1, a th rd resistance 68 isconnectedacross the ralls at approximately maximum braking distance from the exit.end'ot' the" section Line current is constantlysupplied t th e rails ofeach sectionbetween resist ances 768* and 68 -by means of a secondary67fot'fthe' adjacent transformer X, the ter niinals otwhich secondaryare connected with the iniddle points of these two resistances,respectively. Line current is also at times supplied to the rails ofeach section between resistances 68 and 68 by a sec ondary66 on theadjacent transformer T. One'terminal ofsecon'dary 66is constantlyconnected with the middle point of resist ance 68', while the otherterminal is at times fconnectedjwith the 2 middle point of resist- Vance:68 through contact 63 of the track contact fitbeingclosed when thesignal in-i relayfK forthe section next in advance and also throughcontact 64 operated by, the

signal forsuchlsection next in advance,

dicatesproceed'or caution, and open when the signal indicates stop. j I

7 It will'be seen from the foregoing, that line current isalwayssupplied to the rear cportionofeach track section; whereas suchcurrent is'supplied tothe forward portion railwayvehicle, which may beeithera car or a train. Mounted on this vehicle '(see in front of theforward axle are -Fig'.i2)'

-, two'magnetizablecores 69"and"69 located between resistances 68 and68? when the next section is unoccupied, but not when such section isoccupled. I

The reference "character V designates a directly above thetrack; rails 1and-'1 respectively, -Thefcores 69*and 69 are prov1ded-w1th"w1nd1ngs73and 73fwh1ch are connected 4 n a receiving' circuit a in such mannerthat the currents 7 induced in these windings by track circuitcurrentfrom transformer secondaries'57 are cumulative, whereas" thecurrents induced in t e windings by line current from secondaries'66 and67 are in opposition and therefore create '110 current in circuit 05.Also mounted on the vehicle? in a suitable position, such as. in

.the rear of the forward axle, are two other magnetizable cores and 70%,located di xrectly above the track rails 1 and 1*,respectively. Thesecores are provided with windin s 173 and-173 which are included in areceiving circuit 6 in such manner that the currents induced in thesewindings by line current in. the, track rails are'cumulative, whereasthe currents induced'in'these' windings by track circuit currentin thetrack rails'oppose each other and therefore create 110 current in thecircuit Z), a V q The reference character A n designates relaycarried'by the vehicle V,and which wewill term the main'relay. As hereshown,

vthis relay is of the induction motor type,

coinprisinga rotor 2* and two stator wind lngs 3 and 3. The windings 3and 3? are controlled by the energycreated in circuits a and brespectively, by currents in the track rails." interposed between thereceiving circuit a and the relay winding 3 is an amplifying device 71,and'interposed between re ceiving circuit 29' and r-elay winding 3 isanother. amplify ng device/72. These amphi'ying '(lGVlCGS may be of anysuitable vform, and they are not" illustrated in detail hereinbecausethey ,"form no part. of our present invention; The rotor 2 of relay Aoperates a circuit controlling contact'finger V 4:. 'Thecontrol ofrelayA is such that when linecurrent is suppliedto the receiving cir suit I)and, track circuit current of normal relative polarity is supplied toreceiving 011'- cult (athe Contact 'fingere 1s swung to the rlght, whichwe wlllterni the normal position, whereas, whenthe receiving circuit 61s energized and the receivlng circuit a'i's' a'caution signal thisrelay will be energized in reverse direction, whereas, after the vehicle passes the resistance 68 in a caution block, relay A will becomedie-energized" due to the loss or line current.

in such a way that this magnet is" energized directly through contact 4when relay A is energized 111 normal d1rection.At such time theClUQtllt'fQI magnet M passes from terminal B ofa suitable source ofcurrent through contact H ofrelayA, iwirell The main relay A controls amagnet M esa, s14.

magnet M andwiro to terminal U of the same source of current. timesenergized by virtue of another circuit which willbeexplainedhereinafter.

Magnet M controls a valve 5 in such manner that the movable member ofthis valveis in its lowest position when the magnet is energized, and inits highest position when the magnet is dc-energized. V] hen magnet M isenergized the valve 5 connects aieservoir It with the main reservoir ofthe braking system through pipes 8 and 8 This being (the normal positionof valve 5, it. fol lows that reservoir R is normally charged to mainreservoir pressure. When the magnet M'becomes de-energized the reversalof valve 5 serves to disconnect reservoir R from the pipe 8 and toconnect this reservoir with the underside of a piston 7 through a pipe6, the reservoir at the same time being connected with an orifice 9 ofrestricted area which opens to the atmosphere. Unless prevented by othermeans, which will be explained hereinafter, the pressure of reservoir Ron the" underside of piston 7 causes this piston to move upwardlyagainst the action of a spring 22 and to remain in such position untilthe pressure in reservoir R is reduced to acertain value by the exhaustof this pres sure through orifice 9. lVhen piston 7 is elevated, itopensa valve 17 which then connects a pipe 13 with atmosphere through anexhaust portl8.

Pipe'13 controls a brake application valve S. The valve S comprises aslide valve 19 governediby a piston 20 whichpiston is biased to theright by a spring 2a. Both sides of the piston 20 are normally exposedto main reservoir pressure through pipes 8 and 8"anda small orifice 20in the piston 20." It will be seen, therefore, that as long as pipe. 13is closed the air pressures on the opposite sides of piston 20 are equalso that this pistonis held inits right-hand position bythe influence ofspring 2%; slide valve 19 is then in such position that the valve deviceis inactive in that it does not cause an application of the brakes.lVhen pipe 13 is opened to atmosphere, however, the pressure on theleft-hand side of piston 20 is reduced so that this piston and the slidevalve 19 are shifted to the left. l i hen this occurs the pipe 8, whichleads to the engineers brake valve W and to the letthand side of feedvalve 10, is disconnected from the main reservoir; that is, from pipe8", so'that the engineer is 'unable to release the brakes bymanipulation of valve lV. movement of piston 19 causes an application ofthe brakes in the-following manner The exhaust of air from brake pipe 29is controlled by an auxiliary valve 33 which is attached to a piston 26.The upper surface ol 'piStonQB is normally exposed to brakepipe-pressure through pipe 30, chamber 31 Magnet M is at The left-handface owing to the stem of valve 33, so that the piston normally occupiesits lowest position wherein valve 33 is closed. hen the slide valve 19moves to the left, however, the

upper side of piston 26 and the equalizing reservoir BE are disconnectedfrom pipe and are connected witha reduction reservoir RR through chamber31rand pipe 87. The pressure on the upperside of piston 26 is thusreduced by a certain amount so that this piston rises, thereby openingvalve 83 and allowing the brake pipe to exhaust to atmosphere. When thebrake pipe pressure is reduced to a value lower than the equalizedpressure on the upper side of piston26 this piston again movesdownwardly and closes valve 33, thereby preventing a: further reductionof pressure in the brake pipe. By proper groportioning of thetworeservoirs tion may be secured, such, for example, as a reduction of20 lbs.

Returning to piston '7 it will be remembered that upon de-energizationof magnet hi this piston rises and thereby opens pipe 1.3 to atmosphere,and after an interval of time determined by the exhaust of reservoir itthrough orifice 9, this piston returnsto its normal position, therebypermitting valve 17 to return to its closed position and so todisconnect pipe 18 from atmosphere. Main reservoir pressure then buildsup on the lefthand side of pistonQO, so that this piston is againshifted to the right, and the slide valve 19 is thus returned to itsnormal position. The upper side of piston 26 and the equalizingreservoir RE are then again connccted with the-brake pipe 29 throughpipe 38, chamber 81 and pipe 30, whereas the re duction reservoir ER isopened to atmos phere through pipe 87, chamber 39 and exhaust port 40.The brake pipe 29 is then re-charged by main'reservoir pressure frompipe 8 which flows through pipe 8, pipe 8", iced valve 10, pipe 4-1.chamber 42 of engineers valve W, and pipe43 to brake pipe 29. The partsare thus restored to their normal. condition wherein they are ready fora subsequent operation of the brake application valve S.

e0 T HE and Bit, any desired brake pipe reduc- The foregoing operationof the apparatus controlled by magnet-M is the operation that takesplace when the vehiclei passesacaution signal unless the engineer takessuitable action to prevent the automatic application of the brakes. Toenable .the engineer'to do this, means are provided for supplying fluidpressure to the upper surface of piston 7 during. the time interval inwhich this 'pistonwould otherwise be elevated by the pressure fromreservoir R. The supply of pressure to the uppersuriiace otipiston 7 iscontrolled by a manually operable valve J Y i with atmosphere:throughapipe 28 and an orifice 210i restrictedarea. When the handle'of valve' Jis swung'around through 180, the valve serves to connect a reservoir Rwith main 'reservoirthrough pipes 8, 8? and .8, so that the reservoir Rbecomes charged to main reservoir pressure; Ifhan- L indicates cautionandsignal L? indicates proceed. Vehicle V can therefore proceed.

dle J is then'returned to its normal position reservoir. R? isdisconnected from main reservoir and is connected with pipe 28 and alsowith exhaust oriiice 21, so that for a certain time interval, determinedby the flow of air through orifice 21, the UPPGT'SLUEEICQ of piston 7'is supplied with pressure from reservoir R lhelo'wer side of piston 7 isprovided .with an annular rib which 7 cooperates with a gasket inthe endof the cylinderin which. this piston operates, so that when the pistonis down'the effective area exposed to reservoir 1 is considerably lessthan that exposed to reservoir R and so'itiollows'that withequal'pressures in both reservoirsthe piston will remain at itslowestposition. The parts of the apparatus are-so proportioned that if valve 3is reversed and then restored to/its normal position-at the time thatmagnet M becomes g zed, the piston 7 will beheld down by pressure fromreservoirv R until the pressure in reservoir R is reduced below thevalue required to raise the piston. In other words," if the engineeroperates the acknowledging valve 'J at the time that magnet 'M becomesClo-energized he can prevent an automatic applicationLof the lorakesf I-,The vehicle carried apparatus may be provided with-an indicator 128 toshow the engineer at all times the actual condition of the apparatus.This indicator comprises two pressure gages having pointers 28 and 90'Pointer 28- is responsive to the pressure in pipe 28 which connectswith. 'reservoir R and pointer 90 is responsive to the pressure in pipe90 which connects with .i'eservoir lt. When magnet valve M is energized,the pressure supplied toreservoir lt cau'ses pointer 90 to move in aclockwise direction, indicating to the engineer that the L vehicle isunder the protectionof the train driftsslowly toward the left.w'hen'valve control system. 1 When magnetvalve M is de-energized, thepressure in reservoir It is slowly dissipate'd to atmosphere throughrestricted port 9andpointer190. therefore J is in the normal position asshown in the drawing atmospheric. pressure exists n reservo r R andpointer 28 is in its left hand position. When: valve J is reversedhowever, reservoir R is charged to main reservoir pressure and pointer28 is moved to a right'hand-position. If nowvalve J is.

againrestored to normahthis pressure is slowly dissipatedto atmospherethrough port '18 and pointer 28 drifts towardthe left. Completeinformation is thus given 7 the engineer at all times concerning theop-. eration of the apparatus.

In so. far as the apparatus scribed is concerned,'it will be seen thatthe operation is'as follows: I f

Track section E F being occupied by a vehicle V, signal L indicatesstop, signal through section CD at full speed,f'but upon passing signalLP relay A will become reversely energized due to. the' fa'ct that thetrack "circuit current in section DEi is of reverse-relative polarity.The

reversal. of relay A will de-energize magnet M, and so if the engineerfailsato-operate the acknowledging valved thef'brakes will be appliedand the vehicle will be brought to a stop. On the other hand, if theengineer will be obviousthat there nothing to pre vent-the. engineerfrom proceeding through section DE and into section E+-Fatifull 7 speed.It is desirable howeve'r, toprevent such train operation to make surethat the engineer is fully aware that he is approach: ing a' stopsignal. To accomplish'thiswe have provided a slow-operating'fcircuitcon? trollerYwhich is so designed .that its con tact 1212 is normallyopen, but that this thus far decontact closes upon the expiration oif'agiven time interval after the controller becomes energized. This circuitcontroller-maybe,

for example, similar to the controller shown in United StatesLettersPatent No.1,272,972, granted to L.,V.' Lewis on July 16', 1918. Thiscircuit controller is provided with" an energizing circuit whichincludes fcontact ,4l" of relay A,and which circuit willbe obviousfrom'the drawing It wil-lbe seen, therefore, that this circuitcontroller is normally dc-energized but becomes energized when relay Abecomes energized inrreverse direction, that. is;- when the vehiclepasses a caution signal. Atterthe circuit controller Y becomes energizedan interval of time closed, and upon the expiration of thisti neintervala new circuit for magnetM beelapses before contact 12--12becomes;

comes closed, which circuit passes from.terminal B of a suitable sourceof current through contact 12-12 of circuit controller Y, wires let and11, magnet M,and wire l5 to terminal 0 of the same source of current.

The time interval required for the operation acknowledging valve J andthereby prevents an automatic application of the brakes. Circuitcontroller Y becomes energized atthis point and after the expiration ofthe fixed time interval of this circuit controller magnet M againbecomes energized, due to the auxiliary circuit through contact 12-12 ofcontroller Y. Valve 5 is then restored to its normal position whereinreservoir R is charged from the main reservoir and so the I brakeapplication apparatus is restored to the same condition as that whichexists when the vehicle is traveling under a'proceed signal. When thevehicle reaches resistance 68 in section D-E the main relay A be- .comesde-energized, thereby tie-energizing circuit controller Y so thatcontact 12-12 opens immediately. This again causes deenergization ofmagnet M so that unless the engineer takes suitable action'the brakeswill be applied and the vehicle will be brought to a stop. If, however,the engineer operates the acknowledging valve J in the same manner asbefore he is able to prevent the auto- Ina-tic application of thebrakes, but by so doing he shows that he is aware of the fact that he isapproaching a stop signal.

It desirable, a trackway marker G may be placed at resistance 68' ineach section to indicate to the engineer the location of thisresistance.

With the arrangement of trackway apparatus shown in Fig. 1, it will beseen that when a train is approaching a stop signal the secondacknowledgment must be made at location 68*, which is at some distancein the rear of the stop signal, this distance usually beingmaxiinumbraking distance for full speed. In some instances, however, it may bedesirable to eliminate location 68" and provide for the secondacknowledgment or the second brake application at the stop signalitself. To accomplish thisthe trackway apparatus shown in 3 may beemployed, which apparatus is identical to that shown in F i 1, exceptthat resistance 68 is omitted from each track section, and the secondary66 of each transformer T is connected with resistances68" and 68, whichare located at the entrance and exit endsof the section respectively. Inother words, line circuit current is always supplied to the rails ofeach section throughout the entire length of the section.

If an automatic brake application is i'ncurred, as by failure of theengineer topropc-rly acknowledge a change of traffic conditions,the'upward movement of piston-l6 uncovers port 13 and this piston isthereafter heldin an intermediate positionbythe equilibrium between theforce exerted by spring 16 and the unequal pressures'onthe two sides ofpiston 16. l/Vhen thepiston is int-his position, however, pipe 13 isTopento atmosphere through restricted port 18 and the pressure on theleft of piston 20 can not build up high enough to reverse valve S andrelease the brakes. To overcome this difficulty, we provide pipe 13 withaman'ually operable valve Hbymeans ofwhich the pipe 13 may be opened toatmosphere.

lVhen valve H is opened, the decrease in pressure on the under side ofpiston 16 allows this valve to' be moved downward by spring 16, thuscovering port 13 Valve H can now be closed, and pressure builds up H isoperated while the brakes are released,

it will reduce the pressure to the left of pis- The vehicle V mayproceed through section C-D at full speed, because track circuit currentof normal relative polarity is supplied to the rails of this section.Track circuit current of reverse relative polarity is supplied to therails of section DAB, however, and so as the vehicle passes point. D theengineer must operate the acknowledging valve J or an automaticapplication of the brakes will occur. Assuming that the. engineer doesoperate the acknowledging valve J, the train may-proceed through sectionDE and circuit controller Y will then be energized. Upon passing point Ethe circuit controller Y will become de-"ener gized so that an automaticapplication of the brakes will occur unless the engineer again operatesthe acknowledging valve J.

Although we have herein shown and de scribed only two forms of apparatusenibodying our invention, it is understood that various changes andmodifications may bemade therein within the scope of the'ap pendedclaims without departing from the spirit and scope of our invention.

Having thus described our invention, what we claim is: i

1. Railway traflic controlling apparatus on the left hand side of piston20 and re- 1 verses valve S to release the brakes. If valve comprising avehicle, provided with a mag g net, mechanism on said vehicle controlledby sa1d magnet and eiiective for a given in- 'terval of time afterde-energization of the,

ltacts,;a circuit for said magnet controlled hya normal contact-10f saidrelay, a slowclosing electromagnetic circuit controller onthe vehiclehaving a timeelement'at least as'greatas the time intervalof said brakeapplyingmechanism, a circuit for said'controller including a reversecontact of said relay, an auxiliary circuit for said magnet governed bysaid c rcuit controller, and-- means partly on the vehicle and partly inthe trackway forenergizingsaid relay in normal direction under cleartraflic conditions, in reverse dlrection under caution trafiiccondltions and for 'de-energizing the relay under stop conditions.

' 2. Railway traflic controlling apparatus comprising a vehicleprovidedwlth a magnet, mechanismon said vehicle controlled by said magnetandeffective'for a given interval of time after 'de-energization of themagnet to apply the brakes, manually operable imeans on the vehicle forpreventing an application of the brakes during said interval of time, arelay on the vehicle capable of normal and reverse energization, a

slow-closing electromagnetic circuit controller on the vehicle having atimeinterval partly in the trackway and operating under at least asgreat as that of said brake-applying mechanism, means for energizingsaid circuit controllerwhen said relay becomes energized in reversedirection, means for energizing said magnet when said relay is energizedin normal direction, other means for energizing said magnet when saidcircuit controller is closed; and means partly on the vehicle and'partlyin the trackway for energizing said relay in normal direction underclear traflic conditlons, in reverse di-i,

rection under caution trafiic; conditions and for de-energizlng therelay under stop con d1t1ons.

3; Railway trafliccontrolling apparatus "comprising a vehicle providedwith a mag net, mechanismon said vehicle controlled by' said magnet andeffective for a given interval of time after de-energization of themagnet to apply the brakes, manually operable means on the vehicle forpreventing an application ofxthe brakes during said interval of time, arelay on the vehicle capable ofnormal and reverse energization, a'

slow-closing electromagnetic circuit controller on the vehicle having atime interval at;

leastas great as that of said brake-applying mechanism, means, forenergizing said circult controller when said relaybecomes enertrollingsaid magnet jointly by said relay and said circuit controller; and meanspartly on the vehicle and partly in the trackway net, mechanism on saidvehicle controlledby f saidmagnet and effective for a given interval oftime atter de-energization of the mag vnet-to apply the brakes, manuallyoperable means on the-vehicle for preventing an apized in reversedirection, means for conplicationof the brakes during said interval oftime, a slow-closing electromagnetic circuit controller on the vehicle,means for energizing said magnet when said circuit controller is closed;and means partly on the a vehicle and partly in the trackway forenergizing said magnet directly under clear trai fic conditions, forenergizing said circuit controller under caution conditions, and fordeenergizing both said magnet and circuit controller under stopconditions.-

5. Railway trafic controlling apparatus comprising a vehicle providedwithamagnet, mechanism onsaid vehicle controlled by said magnet andeffective for a giveninterval of time after de-energization of themagnet toapply the brakes, manually operable means on thevehicle forpreventing an application of the brakes during said interval of time,means partly on the vehicle and clear traflic conditions to energizesaid magnet, said means operating upon-a change to caution condition tode-energize said magnet for a timeinterval at least as great as the timeinterval-0f said mechanism and'to then re-energize said magnet, and saidmean-s opcrating under stop conditions to tie-energize supplyingasecond' alternating current to the rails'of each section, means foreach section controlled bytrafiic conditions in ad- Vance for reversingthe relative polarity of one of said currents, a vehicle; a relaythereon controlled by said currents in the track rails and assuming anormal condition when Qboth currents-arepresent and thereversiblecurrent is of normal polarity, a reverse condition'when saidreversible current is reversed, and a de-energized condition when eithercurrent isabsent; a magnet on said vehicle, mechanism controlled by saidmagnet andefl'ective'for a given interval of time after the magnet is(lo-energized to apply the vehiclebrakes,manually operable means onweenie the vehicle for preventing an application of the brakes duringsaid interval, a slow-closing electromagnetic circuit controller on thevehicle having a time interval at least as great as that of saidmechanism, a circuit for said controller closed when said relay is inreverse condition, means for energizing said magnet when said relay isin normal condition, and other means for energizing said magnet whensaid circuit controller is closed.

7. Railway traflic controlling apparatus comprising a stretch of railwaytrack dicurrents is normal, and means effective upon reversal of therelative polarity of such currents to actuate said device andsubsequently return it to its ineffective condition and also effectiveupon the interruption of either of such currents to again actuate thedevice.

8. Railway trafiic controlling apparatus comprising a vehicle carriedrelay capable ofene'rgization in a normal or a reverse direction, mean-slocated partly on the vehicle and partlyin the trackway for energizingsaid relay in one direction under clear traffie conditions and in theother direction under caution traffic conditions but for deenergizingthe relay under stop conditions, a device on the vehicle effective whenactuated to apply the brakes, and means for maintaining said device inits ineffective condition when said relay is energized in the normaldirection but for actuating said device and subsequently restoring it toineflective condition when the relay becomes energized in the reversedirection and for again actuating the device when the relay becomesde-energized.

9. Railway traflic controlling apparatus comprising a vehicle carriedrelay capable of energization in a normal or a reverse direction, meanslocated partly on the vehicle and partly in the trackway for energizingsaid relay in one direction under clear tratlic conditions and in theother direction under caution ,traflic conditions but for deenergizingthe relay under stop conditions, a valve on the vehicle arranged whenopened to apply the brakes, and means for keeping said valve in itsclosed. position when said relay is energized in the normal directionand for opening said valve and subsequently reclosing it when the relaybecomes energized in the reverse direction and tor again opening saidvalve when the relay subsequently becomes (ls-energized.

10. Railway trafiic controlling apparatus comprising a stretch ofrailway track, a vehicle carried relay capable of energization in anormal or a reverse direction, means partly on the vehicle an d partlyin the trackway for successively energizing the relay in the normaldirection, energizing the relay in the reverse direction, andale-energizing the relay as the vehicle proceeds from safe to dangerousterritory, a valve on the vehicle arranged when opened toapply thebrakes; and means for keeping said valve-in its closed position whensaid relay is energized in the normalclirection, for opening said valveand subsequently reclosing it when the relay becomes energized in thereverse direction, and for again opening saidvalve when the relaysubsequently becomes deenergized.

11. Railway traliic controlling apparatus comprising a stretch ofrailway track, a railway vehicle, a valve on the vehicle arrangedwhenopened to apply the brakes, and means partly on the train and partly inthe trackway to successively open, close and reopen said valve as thevehicle approaches another vehicle ahead, said means including linecurrent constantly supplied to the track rails and track circuit currentalso constantly supplied to the track rails but controlled as torelative polarity by traflic conditious in advance.

12. Railway traffic controllingapparatus comprising a vehicle providedwith a magnet, mechanism on said vehicle controlled by said magnet andeffective to apply the brakes, a'slow closing electromagnetic circuitcontroller on the vehicle, means for energizing said magnet when saidcircuit controller is closed, and means partly on the vehicle and partlyin the trackway for energizing said magnet under clear traflicconditions and for energizingsaid circuit controller under cautionconditions and for deenergizing both said magnet and said circuitcontroller under stop conditions.

13. Railway traflic controlling apparatus comprising a vehicle providedwith a magnet. mechanism on said vehicle controlled by said magnet andeffective for a given interval of time after de-encrgization of themagnet to apply the brakes, a slow closing electromagnetic circuitcontroller on the vehicle, means for energizing said magnet when saidcircuit controller is closed; and

means partly on the vehicle and partly in the tlEtCl"-.*t1}' f0lenergizing said magnet under clear traliic conditions, for energizingsaid circuit controller under caution conditions, and for deenergizingboth said Inagnet and said circuit controller under stop conditions. i i

' thervehic'le. effective for a time interval to 14 Railway'trafiiccontrolling apparatus comprising a vehicle'provided with a normallyenergized'magnet,mechanism on said vehicle controlled by said magnet andeffective for a given interval of time after deenergization of themagnet to apply the. brakes, and meanspartly on the vehicle and partlyin'the trackway and operating upon a change from clear to cautiontraffic conditions to de energize said magnet for at least the timeinterval ofsaid mechanism. and to then re-energize said magnet, saidmeans operating under stop conditionsto again dea.

energize said magnet. 15. Railway trafiic controlling apparatuscomprising a vehicle carried relay capable of energizat on in a normalor a reverse d1-' rection, meanslocated partly on the vehicle and partlyin the trackway for energizing said relay in one direction under cleartrat fie conditions and in the other direction under caution trafiicconditions but for deenergizing the relay under stopi conditions, a

valve onthe vehicle arranged'when opened to apply the brakes, means forkeeping said valve in its'closed position when said relay is energizedin the normal directionjbut for opening said valve whensaid. relay isenergized in the reverse directionor is deenerglzed, and manuallyoperable means on prevent openingof said valve when said relay isenergized in reverse direction or is V tie-energized.

16. Railway trafiic controlling apparatus comprising a stretch ofrailway track, a

railway vehicle, a valve on the vehicle ar-] ranged when opened toapply. the brakes,

.man'ually'operable means on the vehicle etfective tor an interval oftime to prevent application ofthe brakes when said valve is opened, andmeans partly on the train and partly in the trackway to successivelyopen, closeand reopen said valve as thevehicle approaches another.vehicle ahead.

17. Railway traffic controlling apparatus comprising a vehicleprovided'with a magnet, mechanism'on said vehicle controlled by said magnet andeffective for a given.

interval of time after de energizationof the magnet to apply the brakes,manually operablefmeans on the" vehicle for preventing an application ofthe brakes during such 7 interval oftime, a slow closing electromagneticcircuit controller on the vehicle, means for energizing said magnet whensaid' cir cnit controller is closed; and means partly on the vehicle andpartly in the trackway for energizing said magnet under clear 'trafiicconditions, for energizing said circuit;

controller under caution conditions, and for de-energizing both saidmagnet and said circuitcontroller under stop conditions.

18. Railway: traffic controlling apparatus comprising a vehicle providedwith a nor:

inally energized magnet, mechanism on saidvehicle controlled by saidmagnet and efiective for a given interval of time after deg energizationof the magnet to; apply-the brakes, manually operable means onthevehicl-e for preventing an application of the brakes during suchinterval of time, means partly on the vehicle and partly in the trackwayoperating upon a change from clear to caution traiiic conditions to(ls-energize said magnet for at least the time interval of saidmechanism and to then re-energize said magnet, and said means operatingunder stop conditions to again de-energ ze said magnet.

19.- In combination, a railway track divided into .SCt1OIlS, 1I1(-32IHSfor supplying line current to the rails of each sectioncircuit current,and governing means on the vehicle controlled by said relay.

20 In combination, a stretch of railway track, means for constantlysupplying said stretch with line current throughout its length, 'meansfor supplying said stretch with track circuit current of norm'al orreverse polarity according as trafiic conditions in advance are'safe ordangerous respectively, and train carried brake controlling apparatusresponsive to said two track way currents and controlled in accordancewith the relative polarity thereof, regardless of the speed of thetrain.

21. In combination, a stretch ofrailway track, means for constantlysupplying said stretch with line current throughout its length, meansfor supplying said stretch with track circuit current of normal orreverse polarity according as tratficfconditions in advance are "safe ordangerous re spectively, and train carried; governing means controlledby said two trackway currents and arranged to apply the brakes re'gardless of the speed of the train when the 7 relative polarity of saidtrack circuit current V is reversed. r r

22'. In combination, a railway track divided into sections, means forsupplying line current 'to the rails or each section throughout thelength of the section regardless of traflic conditions in advance, of;

the'section, means for supplying the rails of each section with trackcircuit current of 'normalor reverse relative pola'rityac: cording totraflic conditions in advance of the section,- and train carriedgoverning means controlled by said track currents and responsive toreversals of the relative polarity thereof.

28. In combination, a railway track divided into sections, means forsupplying each section throughout its length with line currentregardless of tratiic conditions in advance and with track circuitcurrent, the relative polarities of which currents are normal or reversedepending on trailic conditions in advance of the section, train carriedmeans controlled by said trackway currents for causing abrakeapplication when the relative polarity of said currents is reversed andalso when either current is discontinued, and manually operable means onthe train for preventing said brake applications.

24. In combination, a railway track divided into sections, means forsupplying each section throughout its length with line currentregardless of traffic conditions in advance and with track circuitcurrent, the relative polarities of Which currents are normal or reversedepending on traliic conditions in advance of the section, a traincarried relay controlled by said currents and thereof as well as tocessation of either current, means for causing a brake application whensaid relay becomes energized in reverse direction and also when saidrelay becomes de-energized, and manually operable means on the train forpreventing said brake applications.

In testimony whereof we affix our signatures.

HENRY W. GRIFFIN. LEMUEL F. HOWARD.

responsive to reversals of relative polarity

